1121-76-2Relevant academic research and scientific papers
New description of substituent effect on electronic spectra by means of substituent constants-VI. Ultraviolet spectra of 4-substituted pyridine N-oxides and blue shifted iodine bands of their EDA complexes with iodine
Uno, Bunji,Kano, Kenji,Kaida, Naoki,Kubota, Tanekazu
, p. 937 - 944 (1989)
Electronic spectra of 4-substituted pyridine N-oxides and their EDA complexes with iodine were studied.The substituent effect on the near u.v. 1A1 intramolecular CT bands of the N-oxides and on the blue shifted iodine bands caused by CT complex formation are discussed in terms of a general equation, theoretically derived in order to describe the substituent effect on electronic spectra by means of substituent constants.The results are quite successful and supported by semi-empirical SCFMO-Cl calculations.Based on the results mentioned above, the character of n-? type N-oxide-iodine CT complexes is also examined.The complex formation constants(log K) and pKa values of the N-oxides correlate especially well, indicating that the CT interaction mechanism cannot be neglected in proton addition reactions such as hydrogen bonding and pKa values.
Identical acyl transfer reactions between pyridine N-oxides and their N-acylonium salts
Rybachenko,Shroeder,Chotii,Kovalenko,Red'Ko,Gierzyk
, p. 1608 - 1612 (2007)
28 identical acyl exchange reactions R-CO-Nu+, X- + Nu between pyridine N-oxides in acetonitrile were studied. Here, X- = BPh 4 - and R = methyl, N,N-dimethylamino, N,N-diethylamino, 4-morpholino, 1-piperidino, N-methyl, N-phenylamino, or N,N-diphenylamino group. The IR and NMR spectroscopic characteristics of acyloxypyridinium salts were determined, and the quantum-chemical parameters of all reagents calculated. The results were subjected to correlation analysis. It was found that the rate of identical acyl transfer reactions was controlled by the interaction of frontier orbitals in the transition state.
A general synthesis of bis(o-azaheteroaryl)methane derivatives from N-oxides of azines and azoles
Szpunar, Magdalena,Loska, Rafa?
, p. 2133 - 2137 (2015)
A general method of preparation of derivatives of bis(o-azaheteroaryl)methanes from aromatic N-oxides is reported, the key step of which is a 1,3-dipolar cycloaddition between N-oxides of azines or azoles and in situ generated terminal difluoroalkenes containing an o-azaheteroaryl substituent at the double bond. Selected products were applied for the preparation of two novel unsymmetrical analogues of BODIPY fluorescent dyes, containing both an imidazole and a quinoline or isoquinoline unit.
Discovery of N-(5-Fluoropyridin-2-yl)-6-methyl-4-(pyrimidin-5-yloxy)picolinamide (VU0424238): A Novel Negative Allosteric Modulator of Metabotropic Glutamate Receptor Subtype 5 Selected for Clinical Evaluation
Felts, Andrew S.,Rodriguez, Alice L.,Blobaum, Anna L.,Morrison, Ryan D.,Bates, Brittney S.,Thompson Gray, Analisa,Rook, Jerri M.,Tantawy, Mohammed N.,Byers, Frank W.,Chang, Sichen,Venable, Daryl F.,Luscombe, Vincent B.,Tamagnan, Gilles D.,Niswender, Colleen M.,Daniels, J. Scott,Jones, Carrie K.,Conn, P. Jeffrey,Lindsley, Craig W.,Emmitte, Kyle A.
supporting information, p. 5072 - 5085 (2017/06/28)
Preclinical evidence in support of the potential utility of mGlu5 NAMs for the treatment of a variety of psychiatric and neurodegenerative disorders is extensive, and multiple such molecules have entered clinical trials. Despite some promising results from clinical studies, no small molecule mGlu5 NAM has yet to reach market. Here we present the discovery and evaluation of N-(5-fluoropyridin-2-yl)-6-methyl-4-(pyrimidin-5-yloxy)picolinamide (27, VU0424238), a compound selected for clinical evaluation. Compound 27 is more than 900-fold selective for mGlu5 versus the other mGlu receptors, and binding studies established a Ki value of 4.4 nM at a known allosteric binding site. Compound 27 had a clearance of 19.3 and 15.5 mL/min/kg in rats and cynomolgus monkeys, respectively. Imaging studies using a known mGlu5 PET ligand demonstrated 50% receptor occupancy at an oral dose of 0.8 mg/kg in rats and an intravenous dose of 0.06 mg/kg in baboons.
Iodine/TBHP-Promoted One-Pot Deoxygenation and Direct 2-Sulfonylation of Quinoline N-Oxides with Sodium Sulfinates: Facile and Regioselective Synthesis of 2-Sulfonylquinolines
Sumunnee, Ladawan,Buathongjan, Chonchanok,Pimpasri, Chaleena,Yotphan, Sirilata
supporting information, p. 1025 - 1032 (2017/02/15)
A highly efficient iodine/TBHP-mediated one-pot deoxygenative and regioselective 2-sulfonylation of quinoline N-oxides with sodium sulfinate salts has been developed. This metal-, base-, and phosphorus-free protocol employs readily accessible and easy-to-handle reagents and can be conveniently carried out at room temperature under mild conditions, providing an alternative access to a series of 2-sulfonylquinolines and other related heteroaryl sulfone products in moderate-to-excellent yields within a short reaction time.
Amines vs. N-Oxides as Organocatalysts for Acylation, Sulfonylation and Silylation of Alcohols: 1-Methylimidazole N-Oxide as an Efficient Catalyst for Silylation of Tertiary Alcohols
Murray, James I.,Spivey, Alan C.
supporting information, p. 3825 - 3830 (2016/01/25)
A comparison of the relative catalytic efficiencies of Lewis-basic amines vs. N-oxides for the acylation, sulfonylation and silylation of primary, secondary and tertiary alcohols is reported. Whilst the amines are generally superior to the N-oxides for acylation, the N-oxides are superior for sulfonylation and silylation. In particular, 1-methylimidazole N-oxide (NMI-O) is found to be a highly efficient catalyst for sulfonylation and silylation reactions. To the best of our knowledge, NMI-O is the first amine or N-oxide Lewis basic organocatalyst capable of promoting the efficient silylation of tert-alcohols in high yield with low catalyst loading under mild reaction conditions.
Highly efficient and selective phosphorylation of amino acid derivatives and polyols catalysed by 2-aryl-4-(dimethylamino)pyridine-N-oxides-towards kinase-like reactivity
Murray, James I.,Woscholski, Rudiger,Spivey, Alan C.
supporting information, p. 13608 - 13611 (2015/01/09)
The chemoselective phosphorylation of hydroxyl containing amino acid derivatives and polyols by phosphoryl chlorides catalyzed by 2-aryl-4-(dimethylamino)pyridine-N-oxides is described.
Grafting of a rhenium-oxo complex on Schiff base functionalized graphene oxide: An efficient catalyst for the oxidation of amines
Khatri, Praveen K.,Choudhary, Shivani,Singh, Raghuvir,Jain, Suman L.,Khatri, Om P.
, p. 8054 - 8061 (2014/05/20)
A rhenium-oxo complex such as methyltrioxorhenium (MTO) has been homogeneously immobilized on a Schiff base modified graphene oxide (GrO) support via covalent bonding. The loading of MTO on GrO nanosheets was monitored by FTIR, TG-DTA, and elemental analyses. The developed heterogeneous catalyst is found to be efficient for the oxidation of various amines to the corresponding N-oxides using hydrogen peroxide as an oxidant in high to excellent yields. At the end of the reaction, the catalyst is readily recovered by filtration and reused for subsequent runs. After the third run, the catalyst showed a marginal decrease in catalytic activity owing to the leaching of the MTO complex from the support. This journal is the Partner Organisations 2014.
Equilibrium of acyl transfer between pyridine N-oxides and their acylonium salts
Rubachenko,Schroeder,Chotii,Kovalenko,Red'ko,Lenska
, p. 1241 - 1246 (2008/12/22)
Transfer of acyl groups from N-acyloxypyridinium salts to pyridine N-oxides in acetonitrile was studied. The equilibrium constants of acyl exchange were determined. These quantities vary in the range covering eight orders of magnitude, depending on the st
Molecular complexes of 4-nitropyridine and 4-nitroquinoline N-oxides with boron trifluoride and hydrogen chloride as intermediates in SNAr reactions
Nizhnik,Andreev,Belashev
scheme or table, p. 1824 - 1830 (2009/09/06)
Complexation of 4-nitropyridine N-oxides with ν- (BF3, HCl) and π-acceptors (tetracyanoethylene, chloranil, 2,3-dichloro-5,6-dicyano-1,4- benzoquinone, 7,7,8,8-tetracyanoquinodimethane) activates the nitro group to nucleophilic replacement by chlorine. Adducts formed by 4-nitropyridine and 4-nitroquinoline N-oxides with boron trifluoride and hydrogen chloride were studied by IR spectroscopy. It was shown that these complexes belong to the n,ν type and that the donor-acceptor interaction therein involves the oxygen atom of the N-oxide group.
